Negative split

A negative split means running the second half of a run or race faster than the first. Even or slightly negative pacing is how most records are set.

• Start the first kilometres 5 to 10 seconds per km slower than your goal pace, then settle in.
• Aim for a second half 1 to 2 % faster: on a 2-hour half marathon, about 1 minute quicker.
• Starting too fast burns through your carbohydrate stores and builds fatigue early: it is the classic reason for slowing down at the end.
• Practise it with progression runs, or long runs that finish at goal pace.

The first kilometres should feel almost too easy.